(SALEM) - Salem's airport project has run into karst issues, according to Cory Harper, an airport planner with BF & S Civil Engineers.

The Salem Leader reports, Harper had reported that initial geotechnical tests indicated karst wasn't a problem. But he also reported that additional testing was needed. Those additional tests indicate there are some voids and Harper recommended a karst mitigation plan be developed.

He explained that if nothing is done, at some point the voids might collapse, which could cause the pavement above it to settle. The voids are 30 to 40 feet deep.

Harper suggested building support columns or pilings which will add support while allowing water to still pass through. Harper added that paving probably won't take place until 2015.

Preparations for earth moving for construction of the new runway are underway. The FAA will cover costs and the work does require a permit from the Indiana Department of Environmental Management.

A tower, located near the new runway, is going to have to be removed or relocated. That could involve the use of eminent domain. Harper says the tower used to belong to AT&T but now belongs to a paging company. Grant Money will cover the relocation.

Plans are also in the works to plant 350 trees in several locations around the county, to replace trees that are being removed for the project. The work is being coordinated with Salem's tree board; the tree board and the air board will make the final determination of where the trees should go.